In SAP UI5 documentation, it is also mentioned that Resource model only supports OneTime binding mode:

button text displayed with default locale

This is for button with text “Jerry”. As I have explicitly pass the locale “en” into constructor of ResourceModel, the 404 error for i18n_en.properties is expected since I don’t create such file under “buttontutorial” folder.

However, why is the second i18n.properties loaded? Let’s first have a look at the state of oAppI18nModel2. Please compare mProperties with the one in oAppI18nModel1. It is empty, so according to the logic in previous chapter, getText will fail to serve.

Fortunately, the UI5 framework has fallback mechanism to try the load the default file instead. See the comment below.